This invention relates to the method of making an elongated welding electrode and particularly a welding electrode which has a high current conduction characteristics and is suitable for continuous welding purposes.
Heretofore, welding rods have been commonly used for welding purposes in which the welding rod consists of a selected metal alloy rod about 30 centimeters long having a welding flux material coated on its surface. Such welding rods can be produced with relatively low cost and yet they provide a good quality weld in application. Furthermore, they only require a rather simple welding equipment to carry out the welding operation. However, welding rods have a relatively short length, such that in the welding operation, it often necessitates using several rods to accomplish the task. Accordingly, the weld formed in the welding operation by using such welding rods would have a plurality of weld sections formed by the use of separate new welding rods. The plurality of weld sections are thus not integrally formed and would have many joints among them. Such non-integrally formed weld sections do not form a strong bond with each other, and they are also not as smooth in appearance as an integrally formed weld. Also in application, about 2 centimeters of one end of the rod must be uncoated to provide the welding current conducting contact; and an additional 3 centimeters of the coated rod are discarded since using too short a welding rod may block the welder's sight of the spot to be welded. Thus for a common 30 centimeters long welding rod, there is at least 5 centimeters of the rod wasted. This amounts to a total of at least 15% wastage. Moreover, since the welding current must pass through the entire length of the rod to its front tip during welding, the ffective amount of current at the tip of the rod actually used for te welding operation is greatly reduced due to the inherent curent resistance of the metal rod. For the above reasons, the efficiency of using welding rod for welding is low.
Attempts have been made to produce an elongated welding electrode by providing the welding metal in a tubular form in which welding flux material is contained within the tube. However, such elongated tubular welding electrode is extremely complex and expensive to produce because of the difficulties of placing the flux material within the tube.